Carburetor



F. C. MOCK Nov. 24 .1925- GARBURETOR Filed Jan. 2, 1918 Patented Nov.24, 1925.

UNITED STATES 1,562,651 PATENT OFFICE.

FRANK C. MOCK, OF CHICAGO, ILLINOIS, ASSIGNQR TO STRQMBERG MOTOR DEVICESCOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

CARBURE'IOR.

. Application filed January 2, 1918. Serial No. 209,811.

To all whom it may concern:

Be it known that I, FRANK'C. Moon,- a citizen of the United States,residing at Chicago, in the county of Cook-and State of 5 Illinois, haveinvented a certain new and useful Improvement in Carburetors, of whichthe following is a full, clear, concise,

and exact description, reference being had to the accompanying drawings,forming a 10 part of this specification.

My invention relates to carburetors. In my prior application, Serial No.154,- 109, filed March 12, 1917, I have disclosed 'and claimed acarburetor embodying some of the broad features of the presentinvention. The present invention is an improve- 7 ment upon that type ofcarburetor.

In my prior application, I disclosed a structure which employs thesuction of the engine to perform the dual function of mixing the. chargeof air and fuel and of raising the fuel to the carburetor, i. e., to theconstant level chamber which forms the im.- mediate supply for thecarburetor. The suction which is generated by running of the engineoperates upon an element to control the amount of air admitted to thecarburetor. The amount of air supplied is always less than that demandedto satisfy the suction, so that there is always sub-atmos phericpressure within the carbureter while it is in operation.

\Vhereas, in the prior device referred to, I employed thesub-atmospheric pressure to draw the fuel to the float chamber, tocontrol the inlet of air and to govern the amount of fuel according tothe position of the air inlet valve, my present invention employs theflow of mixture as the governing 40 basis for the inlet of air and theinletlof fuel to form the charge. In one embodiment 'of my invention,which I have constructed, I employ a compound venturi, determining theopening of the air. inlet valve accondh g to the flow as measured in themain venturi and controlling the quantity of fuel introduoed in the aircurrent by the fiow as meas ured in the secondary, or nozzle venturi.

Thus, the theory ofthe present invention develops itself as follows:

Assume a certain flow of mixture as necessary to the engine running at agiven speed. This requires a certain flow of air and a certain flow offuelto make up the mixture.

The air enters as a perfect gas and remains as such throughout. The fuelenters as a liquid and, if possible, should be converted into. a vaporin order to properly mix and flow with the air; but the present fuel, atatmospheric temperature and pressure, will not do this because itcontains a large per-- centage of constituents having such .high boilingpoints as to prevent vaporization under those conditions.

I have found, incidentally, that by reducing the pressure upon the fuel,itcan-be vaporized to a greater extent. Therefore, I make provision formaintaining the flow of air at sub-atmospheric pressure by placing arestriction upon the entry of air. Considering the flow of mixture as adatum or reference point, I control the restriction in the air inletaccording-to the flow, as determined by the depression in the mainventuri. To gettheproper quantity of fuel into the inflowing air, so asto obtain the proper mixture for the charge, I .draw fuel by means ofthe secondary venturi which is another device dependent upon the flow ofmixture to the engine.

The pressure causing fuel :to flow from the nozzle is the differencebetween the depression in the throat of the small venturi, whichincreases with the air flow, and that on the surface of the fuel in thefloat chamber. "The decrease in the amount of force employed may becompensated for by an in \oreaseiin the size of the fuel openings. The

throp in pressure in the throat of the main venturi acts upon therestriction to govern the quantity of air admitted, and at the same timeit is ample ed to raise fuel to the float'chamber. The rop in pressurein the throat of 'the secondary venturi, being greater, is able to drawale to form the mixture.

The double venturit-hus performs aunique service. Not only can thedifference in pressures be employed by the use of the two venturis, butthe arrangementof the nozzles gasoline at the noz .in the secondaryventuri produces a fine,

even atomization which aidsthe vaporization to a reat degree and putsthe fuel in such a fine y subdivided form that-any part of the fuelwhich is not vaporized by the drop of pressure is carried in suspension.

In order to acquaint those skilled in the art with the manner ofconstructing and is a longitudinal section of a carburetor'lembodying myinvention. J Figure 2 is a fragmentary sectional view taken at rightangles to Figure 1; and

Figure 3' is a diagram hereinafter referred to.

. The body lOof the carburetor is L-shaped in form, having the inlet 11opening to -the atmosphere on the, vertical legfland having the outlet'13 on the horizontallegiz .The outlet 13 communicates withthe manifoldof the engine, a suitable attaching flange 12 being provided formounting the carburetor in such-position. v, 3

The amount of air entering the ,inlet ll is controlled by an automatic vbutterfly valve60. T The quantity of mixture flowing t0 the manifold ofthe engine through the outl'et 13 is controlled by a throttle valve 16,mounted on'a transverse rocking-shaft 17, this throttle valve beingmanually controlled and being of the usual construction, a v,

The automatic inlet controlling valve-60 is mounted upon 'a transverseoscillating shaft 61, having bearings in the sidewalls of the verticalleg. A controlling sprin'gl62 is connected to the valve 6O by meansofithe yoke 63 and has its other end connected to a plug 64projectingthrough the walls of the carburetor. The rock shaft 61 is provided withan external gear segment 65, thissegment being of small radius.Ace-operating gear segment 66 of larger radius meshes withthe gearsegment 65. The segment 66 is mounted on a transverse rockiii shaft 67which is pivoted'in the cap mem er 68 of the diaphragm chamber 69. Thediaphragm chamber is preferably formed integral with the body of thecarburetor, a restricted passageway in plug 69' connecting the diaphragmchamber with the air passage leading into the venturis. The rock shaft67 is provided with'an operating arm 77 which has a rounded head 76lying between the collars 7 5- on the vertical plunger 72. The plunger72 is guided "at ts upper end in guide 73 formed at the centre of thecap 68 and at its lower'end in the bore 7 4, formed in the lower side ofthe diaphragm chamber 69. A flexible diaphragm is con nected to theplunger 72 and this diaphragm has its marginal portion .71 clampedbetween the flanges of the cap 68 -.anl,dithe chamber 69.

The barrel, or throat portion, 15 of the carburetor is' of relativelysmaller diameter than the diameter of the vertical leg and the elbowportion in order to increasethe speedof travel of the mixture at thispoint.

A pair of concentric venturis, consisting of the main or primary venturi52 and the secondaryor nozzle venturi"23, are mount- 'Bd W1tl11I1' thebarrel member 15 and face toward the inlet 11. The secondary or nozzleventuri 23 has its rear end discharging into them-am or primary-venturiat a point slightly beyond the most restricted portion of the primaryventuri.

The carbureting chamber 14 is formed between the venturis and thethrottle valve "16 within the barrel 15.

As previously explained, the flow of mixture to the engine is the basisupon which the control ofthe inlet valve 60 is founded; This inlet valveis a means for securing the necessary drop of pressure for'performingthe various functions hereinafter set out. The venturi, 52 is providedwith a peripheral groove 51 andhas openings 53 between the inner surfaceof the venturi at a point slightly beyond the most restricted portion.

The peripheral groove 51 communicates by way of the passageway 78. withthe interior of the diaphragm, chamber 69. The result of;thisconstructiomis that the drop in pressure,,atflthethroat oftheventuri 52 is prolOO slow air and engine speeds, the static sue tionthrough the system is high and the velocity suction in the throat of themain venturi which'acts on .the openings 53 is low. Thus, at,initialturning over of the engine, a drop in pressure will be caused in thebody of the carburetor, which will act as static suction upon thediaphragm to open the valve 60. Therefore thecombination'of thestatic'and velocity; suctions together is the force that acts upon-thediaphragm 7O and also draws gasoline from the main tank" to thefloatchamber through the valve 47.

At higher speeds the suction in the throat of the main venturiiincreasesand operates as a velocity suction to a greater extent upon thediaphragm 70, so that less static suction actually exists in the chamber80 to overcome the spring 62. This is accompanied "by opening of therestriction valve 60. Finally,-

the suction overcomes the entire tension of the spring 62 and the valve60 will be wide open whereupon velocity suction to a'large extent servesthe purpose of feeding fuel and drawing the same into the floatchamber.

The purpose of the regulation of the valve 60 is to insure that at lowspeeds suflicient suction will be maintained to raise gasoline. from themain tank and at high speeds the valve 60 will be wide open so it willnot offer any appreciable resistance.

It is to be noticed that the spring action tends to close the valve 60with a substantially constant force and the static and velocity suctiontend to open it.- The sum total of the static. and velocity suction isdetermined at all times by' the spring tension, sector ratio, andarea ofd aphragm. The liquid fuel for the mixture is supplied at the openings24 which are arranged about the inner periphery of the secondary ornozzle venturi 23. The immediate supply of fuel for these nozzles iscontained in the float chamber 36 which float chamber is formed by acup-shaped member'secured to the bottom of the .body member of the canburetor.

The nozzle venturi 23 ismOunted in the v ring-shaped head 20 of the post19 which is formed integral with the body-1 0 of the carburetor. Thepost '19 extends down through the bottom wall of the bodyof thecarburetor being somewhat enlarged as indicated with an acceleratingwell structure 27 which comprises the outer sleeve 27" and the innersleeve 27, having the annular -space 28- between them forming theaccelerating well.

The inner sleeve. 27" extends upward in the form of a nozzle 81 whichengages the top of the hollow well casing 26 toform a continuous passagewith the vertical fuel passage which leads to the radial nozzle openings 24 by way of the peripheral groove 22 about the venturi 23.Anannular space 31' is formed between the nozzle 81 and the side wallsof the'well casing 26, and this space comn'iunicates with the interiorof the body of thecarburetor by a bleeding passageway 32. I Bleederopenings 82 are formed in the side walls of the nozzle.8l to cause" thefuel which passes up through the vertical passageway 25' to bethoroughly 1 mixed with fine bubbles ;of air.- The bleeding passageway32 communicates with the interior of the accelerating well 28 bythesmall passageways 3l The accelerating well 28 communicates with theinterior of the sleeve 27. through a series of small holes 33 in theside wallsof the inner. sleeve 27 The accelerating well structure 27 issecured .in

' place by thes'crew threads 29 formed onthe inner surface of the wellcasing 26.] The bottom of the. well casing is closed by the screw plugwhich holds the cupshaped float v ated by the float through the mediumof the arm 43'.

I I employ the drop of pressure created by the flow of mixture to raiseor draw liquid fuel into the float chamber 36. Thus, I am able todispense with a separate fuel feed system. The peripheral groove .51which communicates with the throat of the main venturi is connectedby apassageway 54 with the interior of the float chamber 36. A bleedingopening 82 modifies the suction on the float chamber to the desireddegree.

An idling jet is provided under the lip of the throttle valve 16, thisjet consisting a by-pass 69 formed by a hole under the of the throttleand a suitable nozzle 57 which hasan air inlet 58 and a fuel port 83,which communicates by way of rthe passageways and 56 with the normalwell 35.

The operation of the corburetor is "as follows:

The inlet valve 60 is normally .closed so that as soon as the engine isturned over a depression is created in the entire body of thecarburetor. This depression immediately operates upon the diaphragm 70which, in turn opens the intake valve 60 to let in a certain amount ofair to keep the suction within the carburetor from rising above acertain pre-determined amount. This depression which is initiallycreated is alsoavailable for raising fuel to the float chamber until thefuel stands on about the line This depression, created by the initialturning over of the engine, which may be termed a static suction doesnot draw the fuel fromthe float chamber into the carburatingchamberybecause of equalization of the pressure through the opening 82.As

soon, however, as the. inlet valve 60 opens and a flow of air isinitiated through the venturi tubes. 23 and 52, the reduction inpressure at the throat of each of the venturis will be communicated tothe proper point. The drop of pressure inthe smaller or nozzle venturi23 causes fuel to be raised in the .vertical passageway 25 anddischarged at acts upon the diaphragm 70 and upon the float chamber .36to perform the corresponding function of governing the air inlet andgoverning the raisingof fuel.

Shortly after the initiation of the flow of fuel at the openings 24:,air enters by Way of the passageway 32 bleeding into the fuel as itpasses up through inner sleeve 27? from the normal well 35 to the fuelnozzles 24. Y 1

As the speed of the engine increases, the suction at the openings 24becomes greater and draws fuel more rapidly in proportion to the amountof mixture flowing to the engine. The level in the accelerating wellthen lowers, some of the fuel passing the openings into the main fuelpassageway 25. As the openings 33 are uncovered, air is drawn throughthe bleeding passageway 32 to the openings 31 and through the uncoveredopenings 33 to bleed the jet further, in an attempt to satisfy thesuction.

For accelerating purposes, when the throttle 16 is given a furtheropening movement, the suction within the carbureting chamber 14 and theventuris 52 and 23 will be increased and at the same time the fiow willbe increased, and some of the fuel within the accelerating well willbe'discharged through the corresponding openings 33'into the main fuelpassageway 25 and drawn ofi at the openings 24.

When the flow of mixture through the matically the pressure conditionswithin the venturis 23 and 52 for a certain rate of flowof mixturethrough the carburetor. It willbe seen that the suction within theprimary venturi 52 islower than that-in the secondary or nozzle venturi23. The drop of pressure caused by the main venturi 52 is representedbythe quantity A. This quantity is available for! overning the inletvalve 60 and for drawmg fuel from the main tank to the float chamber.The excess of suction in the .nozzle venturi over thesuction in thethroat of the main venturi is illustrated by the quantity B, Thisquantity is .available for drawingfuel from the tain amount of air whichflows past the lip of the throttle valve 16, fuel being supplied fromthe normal well by the passageway and being bled by the air entering atthe bore 58.

While I employ the double venturi for securing different effects ofsuction, i. e., to secure one suction for raising the fuel and a greatersuction for injecting the fuel into the incoming air, I do not intend tobe limited to the use of the two separate venturis, as it is apparantthat I may employ different points along the length of one of theventuris for obtaining diflerent degrees of suction. Thus, for instance,I may employ the point X in the small venturi 23 for securing thesuction necessary to inject the fuel into' the air for the mixture andmay employ the point Y for securing the suction necessary to draw the,vfuel to the float chamber. In that case, the suction represented by thequantity D would be available for raising fuel and the suctionrepresented by the quantity C would be available for injecting the fuelinto the an, for the mixture.

I do notintend to be limited to the details shown and" described, nor tothe dimensions and proportions illustrated.

I claim:

In a carburetor, the combination of a main barrel having a single airinlet and a mixture outlet, an automatic valve gov-- erning said inlet,a suction controlled element governing said valve, venturi means withinsaid barrel, a suction passageway between said venturi means and saidsuction operative element, and a-connection between said barrel and saidsuction operative element at a point between said valve and saidventuri.

means for modifying the effect of the suc tion on said element.

In witness whereof, I hereunto subscribe my name this 29th day ofDecember, A. D,

. FRANK c. MOCK.

